Integrated equipment for the laser-cutting and bending of pieces of sheet metal is known from Italian Patent Application No. TO95A00569, by the same Applicants, in which the sheets to be cut are held in a vertical plane.
Several problems arise in the laser-cutting of metal sheets held in a vertical position which do not generally occur in more conventional cases in which the metal sheet to be cut rests on a horizontal surface. A first problem arises when cutting is effected along a closed path so as to produce a through-hole, of any profile, in the metal sheet. In this case a waste piece is produced having a shape corresponding to that of the aperture to be formed. At the end of the cutting process, the waste piece could fall towards the laser-focusing head. There is thus a danger of the laser-focusing head being hit by the waste piece, causing jamming or damage to the focusing head. A second problem results from the fact that the metal sheet is generally suspended from its upper horizontal edge and, during working, may oscillate or vibrate so that the distance between the leaser-focusing head and the surface of the sheet metal being cat varies. The focusing head usually has a capacitive distance sensor which adjusts the distance of the head from the surface to be cut. In fact it is important for this distance to be kept constantly at a predetermined value to ensure correct focusing of the laser beam. However, when the sheet metal vibrates or oscillates rapidly, the head cannot follow the movement of the surface because of the inertia of the distance sensor and the kinematic(cinematic) chain which controls the movement of the focusing head in a direction perpendicular to the metal sheet.